Shift workers comprise nearly 20% of the US working population, and exhibit disparately high rates of several cancers, obesity, diabetes, stroke, and circulatory disease. A better understanding of the mechanistic factors contributing to increased morbidity in shift workers is needed before the risks associated with these work schedules can be reduced. Simulated rotating shift work in mice, termed Environmental Circadian Disruption (ECD), leads to sleep loss, accelerates death, and dysregulates innate immune function. ECD-exposed mice exhibit pathologically severe inflammatory responses to bacterial endotoxin and increased infarct size following ischemic stroke. Our preliminary work has helped us establish a hypothesis that ECD disrupts the immune cell molecular circadian clock and produces a novel form of immunosuppression. We posit that this immunosuppression specifically slows anti-inflammatory signaling during an inflammatory challenge due to loss of adequate signaling through the TAM family of receptor tyrosine kinases, resulting in uncontrolled pro- inflammatory cytokine release and pathology. In this grant we will investigate the mechanistic underpinnings of the immunological consequences of ECD using newly developed in vitro ECD paradigms, laying the groundwork for translation of our work to human subjects exposed to laboratory-simulated and real-world shift work. The long term goal of this research effort is to develop screening tools and preventative medical treatments that may mitigate the adverse health consequences associated with work schedules that cause circadian disruption.